Page History

<extra-decision>
        <ComposeWebResourceProvider class="your class name"/>
</extra-decision>

package com.fr.web.struct;

import com.fr.common.annotations.Open;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 扩展子组件的管理器
 */
@Open
public class Registry {

    private static Map<Class<? extends Atom>, LinkedHashSet<Atom>>
            children = new ConcurrentHashMap<Class<? extends Atom>, LinkedHashSet<Atom>>();

    /**
     * 注册某个组件所需要的子组件
     * @param clazz 父组件
     * @param atom 子组件
     */
    public static void register(Class<? extends Atom> clazz, Atom... atom) {
        LinkedHashSet<Atom> set = children.get(clazz);
        if (set == null) {
            set = new LinkedHashSet<Atom>();
            children.put(clazz, set);
        }
        Collections.addAll(set, atom);
    }

    public static void remove(Class<? extends Atom> clazz, Atom... atom) {
        LinkedHashSet<Atom> set = children.get(clazz);
        if (set == null) {
            return;
        }
        set.removeAll(Arrays.asList(atom));
    }


    /**
     * 获取一个组件的所有额外的子组件
     * @param clazz 父组件
     * @return 所有的子组件组成的数组
     */
    public static Atom[] getChildren(Class<? extends Atom> clazz) {
        LinkedHashSet<Atom> set = children.get(clazz);
        if (set == null) {
            return new Atom[0];
        }
        set.remove(null);
        List<Atom> list = new ArrayList<Atom>();
        for (Atom atom : set) {
            Filter filter = atom.filter();
            if (filter == null || filter.accept()) {
                list.add(atom);
            }
        }
        return list.toArray(new Atom[0]);
    }
}